CVE-2025-9515 is a high-severity vulnerability affecting the Multi Step Form WordPress plugin developed by mondula2016, specifically versions up to and including 1.7.25. The vulnerability arises from improper validation of file types during the import functionality, classified under CWE-434 (Unrestricted Upload of File with Dangerous Type). This flaw allows authenticated users with Administrator-level privileges or higher to upload arbitrary files to the web server hosting the affected WordPress site. Because the plugin fails to restrict or validate the file types being uploaded, attackers can potentially upload malicious files such as web shells or scripts that enable remote code execution (RCE). The CVSS v3.1 base score is 7.2, reflecting a high severity due to network attack vector, low attack complexity, requirement for high privileges, no user interaction, and significant impacts on confidentiality, integrity, and availability. Although no public exploits are currently known in the wild, the vulnerability presents a critical risk because it enables attackers with admin access to escalate their control over the server environment, potentially compromising the entire website and underlying infrastructure. The vulnerability affects all versions of the Multi Step Form plugin prior to the release of a patch, which as of the provided data, is not yet available. Given the widespread use of WordPress across many organizations, this vulnerability poses a significant threat to sites using this plugin without proper mitigation.

For European organizations, this vulnerability could have severe consequences. Many European companies rely on WordPress for their corporate websites, e-commerce platforms, and customer engagement portals. An attacker exploiting this vulnerability could upload malicious files leading to remote code execution, resulting in full server compromise. This could lead to data breaches involving sensitive customer or employee information, defacement of websites, disruption of online services, and potential lateral movement within the organization's network. The impact is particularly critical for sectors with strict data protection regulations such as GDPR, where unauthorized access or data leakage could result in substantial fines and reputational damage. Additionally, organizations in finance, healthcare, and government sectors in Europe are prime targets for such attacks due to the value and sensitivity of their data. The requirement for administrator-level access limits the attack surface somewhat, but insider threats or compromised admin credentials remain a realistic risk. The lack of known exploits in the wild currently offers a window for proactive mitigation before widespread exploitation occurs.

European organizations using the Multi Step Form plugin should immediately audit their WordPress installations to identify affected versions. Until an official patch is released, the following specific mitigations are recommended: 1) Restrict administrator access strictly to trusted personnel and enforce strong authentication mechanisms such as multi-factor authentication (MFA) to reduce the risk of credential compromise. 2) Disable or restrict the import functionality of the plugin if possible, or remove the plugin entirely if it is not critical to operations. 3) Implement web application firewall (WAF) rules to detect and block suspicious file upload attempts targeting the plugin's import endpoint. 4) Monitor server logs and WordPress activity logs for unusual file upload activity or unexpected file types being uploaded. 5) Harden the web server environment by disabling execution permissions in upload directories to prevent execution of uploaded malicious files. 6) Regularly back up website data and configurations to enable rapid recovery in case of compromise. 7) Stay alert for official patches or updates from the plugin vendor and apply them promptly once available. These targeted actions go beyond generic advice by focusing on reducing the attack surface related to this specific vulnerability and limiting the potential for exploitation.